Male and female terminals in high current electrical connection systems are currently locked by terminals incorporating exterior plastic interlocking structures. The incorporation of the additional plastic interlocking structures to the exterior of the terminals disadvantageously increases the overall dimensions of the connectors. The increased dimensions of connectors having additional interlocking structures presents a number of design challenges for integration of the connectors into higher current electronics requiring increased electrical connector density.
One improvement to electrical terminals having interior interlocking structures are terminals including a canted coil spring, wherein the coil spring is positioned in a groove machined within the body of the female terminals. Prior coil spring terminals require that the groove be machined within each side of the female terminal body and that the coil spring be inserted into the machined groove in the female terminal body. The cost of the machining in producing each of the prior coil spring terminals is high.
Hybrid Electrical Vehicle (HEV) battery packs consist of number of battery modules, wherein each battery module has a plurality of battery cells. Typically, the battery modules are in electrical communication through module to module series connections and the battery cells are in electrical communication through cell to cell series connections. Currently, existing cell to cell connections use a welding process and module to module connections use nut-bolt fastening methods. These processes cause a variety of manufacturing obstacles and safety concerns.
Welding cell to cell connections presents a number of obstacles in manufacturing and servicing. Welding introduces elevated temperatures to the battery cell, which can damage the battery cell. In certain battery types, such as Lithium Ion batteries, the elevated temperatures associated with welding may be the source of an explosion. Further, when utilized in hybrid electrical vehicle applications, welded cell to cell battery packs are not economical to replace, since welded cells are not serviceable during manufacturing or during consumer maintenance.
Module to module connections require nut and bolt arrangements that also provide a number of difficulties, since this manufacturing method is prone to over-torquring or under-torquing of the nut and bolt fasteners. Additionally, cross threading of the bolts is also common, which may destroy the positive or negative battery post when over-torqued. The concise assembly required for high voltage battery module manufacturing and the need for closely monitored torque control render bolt and nut arrangements uneconomical for high voltage battery module manufacturing.
Further, methods for manufacturing high voltage battery modules present a number of dangers to those handling the high voltage battery modules during and after the manufacturing process. Although, each module usually has less than a 50 volt capacity, battery modules are currently being connected in series in order to meet the increasing demands of high-voltage applications, in which voltage levels on the order of about 100 volts to greater than 600 volts are presenting a number of challenges for ensuring safety during the manufacture of these high voltage connections using typical manufacturing methods.
In light of the above, what is needed is an electrical connector system for high current and high voltage applications that can be manufactured in an economical and safe fashion. Further, a need exists for a maintenance serviceable battery pack in which electrical connectors may be reliably and safely manufactured.